<!DOCTYPE html>
<html lang="zh-CN">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>定位</title>
  <style>
    .father {
      width: 80vw;
      height: 50vw;
      border: 1px solid #000;
      /* 父 - 相对定位 */
      position: relative;
    }

    .one {
      width: 20vw;
      height: 10vw;
      background-color: orange;
      /* 子 - 绝对定位 */
      position: obsolute;
      left: -1vw;
      top: -1xw;
    }

    .two {
      width: 20vw;
      height: 10vw;
      background-color: green;
      position: obsolute;
    }
  </style>
</head>
<body>
  <div class="father">
    <div class="one">one</div>
    <div class="two">two</div>
  </div>
</body>
</html>